1. Field of the Invention
The present invention relates to a simple acoustic playback device for a record disc having a plurality of recording grooves.
2. Description of the Prior Art
A simple acoustic playback device for selective playback from a record disc having a plurality of recording grooves has been developed and disclosed in Japanese Patent Publication No. 19763/1986 corresponding to U.S. Pat. No. 3,712,629 and British Pat. No. 1336749.
In the operaton of this device, as a selector bar is pushed, the bar presses a tapered surface of a stylus-pressure releasing wheel to rotate the latter, so that the stylus pressure releasing rod carried by the releasing wheel is moved together with the wheel to lift the speaker unit and reset the pickup at the starting point of playback on the recording surface of the record disc unit. The selector bar, on the other hand, retains a stopper pin provided on the record disc unit to temporarily stop the rotation of the record disc unit such that a selected recording groove is brought to a position where it can be engaged by the pickup at the playback starting position. As the selector bar is released from the pressing force, the stylus-pressure releasing bar is retracted together with the stylus-pressure releasing wheel to free the speaker unit so that stylus pressure is applied to the pickup.
This device has a drawback in that the pickup may erroneously receive stylus pressure during its movement to the playback starting position and thereby failing to select the desired recording groove unless the user continues to push the selector bar until it is engaged by the stopper pin.
The timing of the engagement between the stopper pin and the selector bar differs depending on the position of the stopper pin and the position of the selector bar such that the user cannot predict the exact time of engagement. This type of simple acoustic playback device, therefore, is unsatisfactory insofar as reliability of the selecting operation and quickness of handling.
In addition, in the conventional simple acoustic playback device having a plurality of recording grooves, the speaker unit has to be stationarily fixed in the casing due to the use of the stylus pressure releasing wheel. On the other hand, the acoustic playback device movably mounting the speaker unit cannot be suitably used in such an apparatus since it is subjected to comparatively strong vibration. In recent years, however, there is a trend for mounting the acoustic playback device having a plurality of recording grooves on automobiles or the like. This in turn gives a rise to the demand for an acoustic playback device having a speaker unit mounted stationarily on the casing and capable of suitably playing back a record disc having a plurality of recording grooves.